For cosine (well, and everyone else, too)

Please note, I read all I can on the subject of equipment by Mr. Tom Wishon. He currently runs his own company (www.wishongolf.com, www.twgolftech.com), but was the head clubhead designer at GolfSmith for years. When it comes to clubs, he knows his shit. I'm trying hard to learn his shit, so that I can know my shit. Get it?

Anyway, in another thread I said: I could start a whole thread about club design... like why there's a 1/2" step between clubs, why 'D0' and 'C8' are the 'standard' swingweights, why graphite shafted clubs are longer than steel shafted...

It actually has everything to do with swingweight, believe it or not. Now, a little bit about swingweight. First, it's a build parameter, not a fitting parameter. You don't fit a golfer into such and such a swingweight club. No, really, you don't. You fit them into a club that they hit well, and note the swingweight.

Now, the reason behind almost all the 'things' from the second paragraph is swingweight - and keeping it constant. However, the next topic has swingweight as a secondary consideration.

So for the 1/2" step; the headweight of each club goes up (or is supposed to) by 7g/head. That means if your 3 iron was 10g, your 4 iron would be 17g, your 5i 23g, and so on. Now, the tolerance from the manufacturer is +/- 3g. So what? Well, I'll explain that in a minute.
For those of you who have built clubs, you'll notice the same thing I did. While most tip-trimming instructions ask you to take progressively more tip trim as you work down the irons (from 3 to PW), usually in 0.5" steps, when you butt-cut them to length, all the butt cuts seem to be the same length. So this says what? That we take more and more off the tip the shorter the irons become. Why is this? First, it's to keep the shafts playing to the same flex. The progressively heavier heads need progressively stiffer shafts, so that they'll all play to the same flex, right? And somewhere along the line, we figured that a 0.5" step in the stiffness trim would go along well with a 7g weight increase. (obviously, as it seems to be the defacto standard). But lets remember that those tolerances for head weights are +/- 3g. So if you get your 5 iron at +3g, and your 6 iron at -3g, now there's only 1g weight difference between them. But I'll bet you your house that the 6 iron has 0.5" more removed from the tip than the 5 iron. Don't even get me started on +/- for lofts, and why two clubs are close to each other in distance...

OK, so, in a nutshell, the reason for the 0.5" step in clubs is so they'll all play to the same flex, ideally

OK, so now we have why D0 and C8 are standard swingweights. The answer is dead simple, and if you take a couple seconds, you'll figure it out.







Time's up! Did you get it?

Exactly. D0 and C8 are default standard swingweights, because that's what modern clubs naturally default to (if built to spec). A 38" 5 iron will spec out roughly D0 (men's standard). For some reason, a ladies club is only 1" shorter - which translates into 2 swingweight points - leaving us with C8. That's why it's standard - because big companies don't have to modify anything, they just cut and glue. I wish the answer was fancier than that... but it's not.

OK, so, in a nutshell, the reason for the D0 and C8 being standard is because that's what naturally occurs for modern specs

Finally: The truth about why graphite shafted clubs are 1" longer than their steel shafted brothers.

First, let's dispel the myth. It has nothing to do with more swing speed because of the lighter shaft, or because with the lighter shaft you can go longer. No! No! Lies! A pack of lies! Well, a pack of... well, ok. It's true. But not for the reasons that the OEM's have shoved down your throat.

Yes, you can swing lighter things faster. A 16 oz claw hammer is swung faster than a 6 lb sledgehammer. It's true. But if we take that 16 oz claw hammer, and put it on the same shaft as the sledgehammer, it might be tougher to control. But I digress. Yes, lighter shafts can be swung faster. That's a no brainer. But what does it have to do with making the club 1" longer? Swingweight. Yep. The lighter shaft lessens the swingweight.

So a club that's built with a steel shaft at D0 will swingweight around C7 or C8 if built with a lighter shaft. So we build it 1" longer (roughly 2 swingweight points), so that it's back to D0. (My apologies to the ladies for using solely mens' references). It has nothing to do with 'trying to net your more distance.' That's just a convenient out. In fact, the extra length may hurt some golfers, as you don't find the sweetspot as often (because of that extra length).

OK, so, in a nutshell, the reason for the extra length in graphite shafts is to keep the swingweight up.


I actually had a neat experiment play out on the course today.

I normally play a driver at 45", with a 78g shaft, and a 200g head (this is heavier than most drivers, FYI). It swingweights around D5 - so it's 'heavy' by all standards. Not bad - I tend to fade it. I put a driver into play today at 43.75", with a 62g shaft, a 199g head, and added 4g in shaft tip. Draw after draw after draw.... go figure. If I had to guess, I'd say it swingweighted around C6 or C7 (I just glued it up with quick set, I didn't really spec it).

For those that are interested, I've MOI matched my irons, and they start at C9 SW in the 5 iron and progress to D1.5 in the PW - a 0.5 SW progression. Now that I'm swinging better, and after seeing the results in the driver, I'm thinking about shortening the clubs, and bending them to suit. This will naturally lower the swingweight... but swingweight is a build spec, not a fitting spec.

__________________
True Length Technology Fitter - www.truelengthtechnology.com
It's live! - www.ShipShapeClubs.com
PCS Class 'A' Clubfitter

A new highlight: Golfing the home course on Christmas Day.

I say it too often: If it's golf club shaped, you can play with it.

For the record, I'm a club doctor, not a swing doctor.

hi lp42
looks like you know your sh*t to me!